With a host of cold- and slush-busting features, KEEN® Revel IV Polar Boots can stride into whatever winter throws at you. Heat-holding KEEN.WARM insulation keeps feet toasty down to a teeth-rattling -40°F. A KEEN.DRY waterproof/breathable membrane blocks out moisture while letting vapor escape, so your feet won’t feel like they’re trapped in a sauna. The Thermal Heat Shield footbed deflects cold. Heat Trapolator technology holds onto heat with an outer layer of woolly softness, a middle layer of support cushioning and a thermal foil barrier to harness radiant heat. And true to KEEN form, they offer superior cushioning, ankle support and stability, plus plenty of room for your toes to spread out. Last but not least, the leather is sourced from a Leather Working Group-certified tannery, so you can feel good about stepping more lightly on the Earth, too.